The purpose of the Core of this TDRU Program Project is to provide the following central services for the Program participants. (1) The Core will provide facilities and staff who will carry our An. Gambiae germ line transformation experiments and maintain An. Gambiae colonies used in and produced by these experiments. The only other PI with the capacity for An. Gambiae germ line transformation is Dr. Marcelo Jacobs-Lorena, and it is quite probably that his insectary capabilities would rapidly become saturated without the assistance of the Core. (2) The Core will also assist in Ae. Aegypti germ line transformation experiments. Both Drs. Raikhel and Jacobs-Lorena have the facilities for Ae. Aegypti germ line transformation, and most such experiments will probably be done in their laboratories, but the PI has direct experience with this type of work and the Core is likely to provide at least assistance in such experiments. (3) The Core will also carry out all work involving infecting Ae. Aegypti with P. gallinaceum (supervised by Dr. David Severson). (4) Finally, the Core has the budget for travel to the NIH laboratory of David Kaslow for infecting transformed strains of An. Gambiae with P. falciparum from culture. All aspects of such experiments (coordinating production of mosquitoes and parasites arranging for the travel) will be responsibility of the Core, although the actual experiments themselves may be carried out by the responsible PI.